Low-lead bismuth-free silicon-free brass

ABSTRACT

The invention relates to a low-lead bismuth-free silicon-free brass alloy with excellent cutting performance, comprising, by the total weight of the brass alloy, 60-65 wt % copper, 0.1-0.25 wt % lead, 0.1-0.7 wt % aluminum, 0.05-0.5 wt % tin, one or more element selected from the group consisting of 0.05-0.3 wt % phosphorus, 0.05-0.5 wt % manganese and 0.001-0.01 wt % boron, and a balance of zinc.

CROSS-REFERENCE TO RELATED APPLICATION

This application is the U.S. national phase of International Application No. PCT/CN2014/074938, filed on Apr. 9, 2014, which claims the priority benefit a Chinese Patent which is application No. 2014100039995, filed on Jan. 3, 2014. The entire contents of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a low-lead brass alloy, and particularly to a brass alloy which is both free cutting and resistant to dezincification.

2. Background of Invention

Generally, the brass for processing is added with metallic zinc by a percentage of 38-42%. In order to make it easy to process brass, brass usually contains 2-3% lead to enhance strength and processability. Lead-containing brass has excellent moldability (making it easy to fabricate products of various shapes), cutting performance, and abrasion resistance, so that it is widely applied to mechanical part with various shapes, accounts for a large proportion in the copper industry, and is well known as one of the most important basic material in the world. However, during the production or use of lead-containing brass, lead tends to dissolve in the solid or gas state. Medical studies have shown that lead can bring about substantial damage to the human hematopoietic and nervous systems, especially children's kidneys and other organs. Many countries in the world take the pollution and hazard caused by lead very seriously. The National Sanitation Foundation (NSF) sets a tolerance of lead element of 0.25% or less. Organizations like the Restriction of Hazardous Substances Directive (RoHS) of European Union successively stipulate, restrict and prohibit the usage of brass with a high lead content.

Furthermore, when the zinc content in brass exceeds 20 wt %, the corrosion phenomenon of dezincification is prone to occur. Especially when brass is exposed to the chloride rich environment, e.g. marine environment, the occurrence of corrosion phenomenon of dezincification may be accelerated. Dezincification may severely destroy the structure of brass alloy, so that the surface strength of brass products is reduced and the brass tube even perforates. This greatly reduces the lifetime of brass products and causes problems in application.

Therefore, there is a need to provide an alloy formula for solving the above problems, which can replace the brass with a high lead content, is dezincification corrosion resistant, and further has excellent casting performance, forgeability, cutting performance, corrosion resistance and mechanical properties.

BRIEF SUMMARY OF THE INVENTION

As known in the prior art, silicon may appear in the alloy metallographic structure as γ phase (sometimes as κ phase). In this case, silicon may replace the function of lead in the alloy to an extent, and improve cutting performance of the alloy. Cutting performance of the alloy increases with the content of silicon. However, silicon has a high melting point and a low specific gravity and is prone to be oxidized. As a result, after silicon monomer is added into the furnace in the alloy melting process, silicon floats on the surface of alloy. When the alloy is melt, silicon will be oxidized into silicon oxides or other oxides, making it difficult to produce silicon-containing copper alloy. In case silicon is added in the form of Cu—Si alloy, the economic cost is increased.

Bismuth can be added to replace lead for forming cutting breakpoints in the alloy structure to improve cutting performance. However, thermal cracking is prone to occur during forging in case of a high bismuth content, which is not conducive for producing.

Thus, it is an object of the invention to provide a brass alloy which exhibits excellent performance like tensile strength, elongation rate, dezincification resistance and cutting performance, which is suitable for cutting processed products that require high strength and wear resistance, and which is suitable for constituent materials for forged products and cast products. The brass alloy of the invention can securely replace the alloy copper with a high lead content, and can completely meet the demands about restrictions on lead-containing products in the development of human society.

To achieve the above object, the inventors have proposed the following low-lead bismuth-free silicon-free brass alloys.

A low-lead bismuth-free silicon-free brass alloy with excellent cutting performance (hereinafter referred to as the inventive product 1) comprises, by the total weight of the brass alloy, 60-65 wt % copper, 0.1-0.25 wt % lead, 0.1-0.7 wt % aluminum, 0.05-0.5 wt % tin, and a balance of zinc.

In the inventive product 1, the content of lead is reduced to 0.1-0.25 wt %, the content of copper is controlled at 60-65 wt %, and a small quantity of aluminum and tin is added to improve cutting performance of the alloy. The metallographic structure of the alloy mainly comprises a phase, β phase, γ phase, and soft and brittle intermetallic compounds which are distributed in grain boundaries or grains. Copper and zinc make main constituents of the brass alloy.

Adding tin into the alloy can form γ phase, thus increasing cutting performance of the alloy. In addition, the addition of tin obviously increases strength, plasticity, and corrosion resistance of the alloy. However, since adding tin may increase cost, aluminum is added along with tin. As a result, not only cutting performance of the alloy can be improved, but also strength, wear resistance, cast flowability, and high temperature oxidation resistance of the alloy can be increased. In order to make a better use of the above effects, the content of tin and aluminum is 0.05-0.5 wt % and 0.1-0.7 wt %, respectively.

A low-lead bismuth-free silicon-free brass alloy with excellent cutting performance (hereinafter referred to as the inventive product 2) comprises, by the total weight of the brass alloy, 60-65 wt % copper, 0.1-0.25 wt % lead, 0.1-0.7 wt % aluminum, 0.05-0.5 wt % tin, and further comprises 0.05-0.5 wt % manganese and/or 0.05-0.3 wt % phosphorus, and a balance of zinc.

As compared with the inventive product 1, the inventive product 2 is further added with 0.05-0.3 wt % phosphorus and/or 0.05-0.5 wt % manganese. Although phosphorus can't form γ phase, phosphorus has a function of facilitating a good distribution of γ phase, thus increasing cutting performance of the alloy. Meanwhile, in case phosphorus is added, γ phase will disperse crystal grains of the primary α phase, thus increasing casting performance and corrosion resistance of the alloy. When the content of phosphorus is lower than 0.05 wt %, phosphorus can not play its role effectively. While when the content of phosphorus is higher than 0.3 wt %, casting performance and corrosion resistance will be affected adversely. Adding manganese helps to improve dezincification resistance and cast flowability. When the content of manganese is lower than 0.05 wt %, manganese can not play its role effectively. While when the content of manganese is 0.5 wt %, manganese can play its role to the saturation value.

A low-lead bismuth-free silicon-free brass alloy with excellent cutting performance (hereinafter referred to as the inventive product 3) comprises, by the total weight of the brass alloy, 60-65 wt % copper, 0.1-0.25 wt % lead, 0.1-0.7 wt % aluminum, 0.05-0.5 wt % tin, and further comprises one or more element selected from the group consisting of 0.05-0.3 wt % phosphorus, 0.05-0.5 wt % manganese and 0.001-0.01 wt % boron by the total weight of the brass alloy, and a balance of zinc.

As compared with the inventive product 2, the inventive product 3 is further added with trace boron, so as to better suppress alloy dezincification, increase the mechanical strength, and alter defect structure of cuprous oxide film on the surface of copper alloy, thus forming a cuprous oxide film which is more uniform, dense, and stain resistant. When the content of boron is lower than 0.001 wt %, boron can't play its role as mentioned above. While when the content of boron is higher than 0.01 wt %, the above performance can't be further increased. Thus, the optimum content of boron is 0.001-0.01 wt %. The content of phosphorus and manganese has the same interval as that of the inventive product 2, and this is based on the same reason as that of the inventive product 2.

A low-lead bismuth-free silicon-free brass alloy with excellent cutting performance (hereinafter referred to as the inventive product 4) comprises, by the total weight of the brass alloy, 60-65 wt % copper, 0.1-0.25 wt % lead, 0.1-0.7 wt % aluminum, 0.05-0.5 wt % tin, 0.05-0.3 wt % phosphorus, and further comprises 0.05-0.5 wt % manganese and 0.001-0.01 wt % boron, and a balance of zinc.

The effects of lead, aluminum, tin, phosphorus, manganese and boron elements in the brass alloy have been discussed above. By adding these elements into the brass alloy simultaneously, it is possible to further increase mechanical performance of alloy so as to meet needs for products with strict requirements.

A low-lead bismuth-free silicon-free brass alloy with excellent cutting performance (hereinafter referred to as the inventive product 5) comprises, by the total weight of the brass alloy, 60-65 wt % copper, 0.1-0.25 wt % lead, 0.1-0.7 wt % aluminum, 0.05-0.5 wt % tin, 0.05-0.3 wt % phosphorus, 0.05-0.5 wt % manganese and 0.001-0.01 wt % boron, and a balance of zinc, and further comprises unavoidable impurities which comprise, by the total weight of the brass alloy, 0.25 wt % or less nickel, 0.15 wt % or less chrome and/or 0.25 wt % or less iron.

As compared with the inventive product 4, the inventive product 5 further comprises some unavoidable impurities, i.e., mechanical impurities of nickel, chrome and/or iron.

A low-lead bismuth-free silicon-free brass alloy with excellent cutting performance (hereinafter referred to as the inventive product 6) comprises, by the total weight of the brass alloy, 60-65 wt % copper, 0.1-0.25 wt % lead, 0.1-0.7 wt % aluminum, 0.05-0.5 wt % tin, 0.05-0.3 wt % phosphorus, 0.05-0.5 wt % manganese and 0.001-0.01 wt % boron, and a balance of zinc, wherein a total content of aluminum, tin, phosphorus, manganese and boron is not larger than 2 wt % of the total weight of the brass alloy.

A low-lead bismuth-free silicon-free brass alloy with excellent cutting performance (hereinafter referred to as the inventive product 7) comprises, by the total weight of the brass alloy, 60-65 wt % copper, 0.1-0.25 wt % lead, 0.1-0.7 wt % aluminum, 0.05-0.5 wt % tin, 0.05-0.3 wt % phosphorus, 0.05-0.5 wt % manganese and 0.001-0.01 wt % boron, and a balance of zinc, wherein a total content of aluminum, tin, phosphorus, manganese and boron is 0.2-2 wt % of the total weight of the brass alloy.

A low-lead bismuth-free silicon-free brass alloy with excellent cutting performance (hereinafter referred to as the inventive product 8) comprises, by the total weight of the brass alloy, 60-65 wt % copper, 0.1-0.25 wt % lead, and two or more elements selected from the group consisting of, by the total weight of the brass alloy, 0.1-0.7 wt % aluminum, 0.05-0.5 wt % tin, 0.05-0.3 wt % phosphorus, 0.05-0.5 wt % manganese and 0.001-0.01 wt % boron, and a balance of zinc.

Whether aluminum, tin, phosphorus, manganese and/or boron should be added depends on the requirement for cutting performance of various products. The content to be added has the same interval as that of the inventive product 3, and this is based on the same reason as that of the inventive product 3.

A low-lead bismuth-free silicon-free brass alloy with excellent cutting performance (hereinafter referred to as the inventive product 9) comprises, by the total weight of the brass alloy, 60-65 wt % copper, 0.1-0.25 wt % lead, and two or more elements selected from the group consisting of, by the total weight of the brass alloy, 0.1-0.7 wt % aluminum, 0.05-0.5 wt % tin, 0.05-0.3 wt % phosphorus, 0.05-0.5 wt % manganese and 0.001-0.01 wt % boron, and a balance of zinc, and further comprises unavoidable impurities which comprise, by the total weight of the brass alloy, 0.25 wt % or less nickel, 0.15 wt % or less chrome and/or 0.25 wt % or less iron.

As compared with the inventive product 8, the inventive product 9 further comprises some unavoidable impurities, i.e., mechanical impurities of nickel, chrome and/or iron.

A low-lead bismuth-free silicon-free brass alloy with excellent cutting performance (hereinafter referred to as the inventive product 10) comprises, by the total weight of the brass alloy, 60-65 wt % copper, 0.1-0.25 wt % lead, 0.05-0.5 wt % tin and 0.05-0.3 wt % phosphorus, and a balance of zinc.

The content of phosphorus in the inventive product 10 has the same interval and effect as that in the inventive product 2. Although phosphorus can't form γ phase, phosphorus has a function of facilitating a good distribution of γ phase. Meanwhile, in case phosphorus is added, γ phase will disperse crystal grains of the primary α phase, thus increasing casting performance and corrosion resistance of the alloy. Thus, even if there is no aluminum, the needs for cutting performance can still be met in the usual production situation.

A low-lead bismuth-free silicon-free brass alloy with excellent cutting performance (hereinafter referred to as the inventive product 11) comprises, by the total weight of the brass alloy, 60-65 wt % copper, 0.1-0.25 wt % lead, 0.05-0.5 wt % tin and 0.05-0.3 wt % phosphorus, and further comprises two or more elements selected from the group consisting of 0.1-0.7 wt % aluminum, 0.05-0.5 wt % manganese and 0.001-0.01 wt % boron by the total weight of the brass alloy, and a balance of zinc.

Whether aluminum, manganese and/or boron should be added depends on the requirement for cutting performance of various produc. The content to be added has the same interval as that of the inventive product 3, and this is based on the same reason as that of the inventive product 3.

A low-lead bismuth-free silicon-free brass alloy with excellent cutting performance (hereinafter referred to as the inventive product 12) comprises, by the total weight of the brass alloy, 60-65 wt % copper, 0.1-0.25 wt % lead, 0.05-0.5 wt % tin and 0.05-0.3 wt % phosphorus, two or more elements selected from the group consisting of 0.1-0.7 wt % aluminum, 0.05-0.5 wt % manganese and 0.001-0.01 wt % boron by the total weight of the brass alloy, and further comprises unavoidable impurities which comprise, by the total weight of the brass alloy, 0.25 wt % or less nickel, 0.15 wt % or less chrome and/or 0.25 wt % or less iron, and a balance of zinc.

As compared with the inventive product 11, the inventive product 12 further comprises some unavoidable impurities, i.e., mechanical impurities of nickel, chrome and/or iron.

The invention further provides a method for fabricating brass alloy. By taking the inventive product 3 as an example, the method comprises the steps of:

1) providing copper and manganese and heating to 1000-1050° C. to form a copper-manganese alloy melt;

2) decreasing the temperature of the copper-manganese alloy melt to 950-1000° C.;

3) covering the surface of copper-manganese alloy melt with a glass slagging agent;

4) adding zinc to the copper-manganese alloy melt to form a copper-manganese-zinc melt;

5) deslagging the copper-manganese-zinc melt, and adding lead, aluminum, tin to the brass alloy melt to form a metal melt;

6) elevating the temperature of the metal melt to 1000-1050° C., and adding boron copper alloy, phosphorus copper alloy to form a low-lead bismuth-free silicon-free brass alloy melt; and

7) discharging the brass alloy melt for casting to form the brass alloy.

Preferably, in the above fabricating method, a copper-manganese alloy is provided as the precursor of copper and manganese elements.

Preferably, in the above fabricating method, the melting furnace is a high-frequency melting furnace, and the high-frequency melting furnace is provided with a furnace lining of graphite crucible.

The high-frequency melting furnace has the features of a large melting rate, a large temperature elevating rate, cleanness without pollution, and the ability of self-stirring (i.e., under the action of magnetic field lines) during melting.

In the invention, the low-lead bismuth-free silicon-free brass alloy is formed by adding various constituents in respective ratio, and then subjecting them to a process in a high-frequency melting furnace. The resulting brass alloy has a mechanical processability which is comparable with that of the existing lead-containing brass, has an excellent tensile strength, elongation rate, and dezincification resistance, and has a low content of lead. As a result, the brass alloy is suitable for replacing the existing lead-containing brass alloy and for producing parts like faucet and sanitary ware.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart illustrating a method for fabricating the inventive product 3.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The technical solutions of the invention will be described expressly by referring to embodiments thereof.

It is not intended to limit the scope of the invention to the described exemplary embodiments. The modifications and alterations to features of the invention as described herein, as well as other applications of the concept of the invention (which will occur to the skilled in the art, upon reading the present disclosure) still fall within the scope of the invention.

In the invention, the wording “or more”, “or less” in the expression for describing values indicates that the expression comprises the relevant values.

The dezincification corrosion resistant performance measurement, as used herein, is performed according to AS-2345-2006 specification in the cast state, in which 12.8 g copper chloride is added into 1000 C.C deionized water, and the object to be measured is placed in the resulting solution for 24 hr to measure a dezincification depth. ⊚ indicates a dezincification depth of less than 100 μm; ∘ indicates a dezincification depth between 100 μm and 200 μm; and

indicates a dezincification depth larger than 200 μm.

The cutting performance measurement, as used herein, is performed in the cast state, in which the same cutting tool is adopted with the same cutting speed and feed amount. The cutting speed is 25 m/min (meter per minute), the feed amount is 0.2 mm/r (millimeter per number of cutting edge), the cutting depth is 0.5 mm, the measurement rod has a diameter of 20 mm, and C36000 alloy is taken as a reference. The relative cutting rate is derived by measuring the cutting resistance.

The relative cutting rate=cutting resistance of C36000 alloy/cutting resistance of the sample.

⊚ indicates a relative cutting rate larger than 85%; and ∘ indicates a relative cutting rate larger than 70%.

Both the tensile strength measurement and the elongation rate measurement, as used herein, are performed in the cast state at room temperature as an elongation measurement. The elongation rate refers to a ratio between the total deformation of gauge section after elongation ΔL and the initial gauge length L of the sample in percentage: δ=ΔL/L×100%. The reference sample is a lead-containing brass with the same state and specification, i.e., C36000 alloy.

According to measurement, the proportions for constituents of C36000 alloy are listed as follow, in the unit of weight percentage (wt %):

copper zinc bismuth antimony manganese aluminum lead iron Material No. (Cu) (Zn) (Bi) (Sb) (Mn) (Al) tin (Sn) (Pb) (Fe) C36000 alloy 60.53 36.26 0 0 0 0 0.12 2.97 0.12

FIG. 1 is a flow chart illustrating a method for fabricating the inventive product 3, which comprises the steps of:

Step S100: providing copper and manganese. In this step, a copper-manganese alloy can be provided as the precursor of copper and manganese elements.

Step S102: heating the copper-manganese precursor alloy to 1000-1050° C. to form a copper-manganese alloy melt. In this step, the copper-manganese alloy can be added into the high-frequency melting furnace, and heated to melt in the melting furnace. The temperature can be elevated to 1000-1050° C., and even up to 1100° C., for 5-10 minutes, so that the copper-manganese alloy is melt into a copper-manganese alloy melt. With these actions, it is possible to prevent the melt copper manganese from absorbing a lot of external gases (due to a too high temperature), which may otherwise result in cracking in the molded alloy.

Step S104: decreasing the temperature of the copper-manganese alloy melt to 950-1000° C. In this step, when the temperature in the melting furnace is elevated to 1000-1050° C. for a durationi of 5-10 minutes, the power supply of the high-frequency melting furnace is turned off, so that the temperature in the melting furnace is reduced to 950-1000° C., while the copper-manganese alloy melt is maintained in the melt state.

Step S106: covering the surface of copper-manganese alloy melt with a glass slagging agent. In this step, the surface of copper-manganese alloy melt is covered with the glass slagging agent at 950-1000° C. This step can effectively prevent the melt from contacting the air, and prevent zinc to be added in the next step from boiling and evaporating due to melting at a high temperature of 950-1000° C.

Step S108: adding zinc to the copper-manganese alloy melt to form a copper-manganese-zinc melt. In this step, zinc is added to the melting furnace, and is immersed into the copper-manganese alloy melt, so that zinc is sufficiently melt in the copper-manganese alloy melt to form a copper-manganese-zinc melt.

Step S110: deslagging the copper-manganese-zinc melt. In this step, the copper-manganese-zinc melt can be stirred and mixed under the action high-frequency induction, and then the slagging agent can be removed. Then, the copper-manganese-zinc melt is deslagged with a deslagging agent.

Step S112: adding lead, aluminum, and tin to the copper-manganese-zinc melt to form a metal melt. In this step, copper lead precursor alloy, copper aluminum precursor alloy, and copper tin precursor alloy can be added to the copper-manganese-zinc melt.

Step S114: elevating the temperature of the metal melt to 1000-1050° C., and adding copper boron alloy and phosphorus copper alloy to form a low-lead bismuth-free silicon-free brass alloy melt.

Step S116: discharging the brass alloy melt for casting to form the brass alloy. In this step, the brass alloy melt is stirred evenly, the discharging temperature is controlled at 1000-1050° C., and finally the brass alloy melt is discharged to casting a low-lead bismuth-free silicon-free brass alloy which exhibits good processability, dezincification resistance, and mechanical performance.

Embodiment 1

Table 1-1 lists inventive products 1 with 5 different constituents which are fabricated with the above process, which are respectively numbered as 1001-1005, each constituent being in the unit of weight percentage (wt %).

TABLE 1-1 No. copper (Cu) zinc (Zn) lead (Pb) aluminum (Al) tin (Sn) 1001 63.633 35.559 0.235 0.231 0.340 1002 64.365 34.183 0.250 0.700 0.500 1003 62.345 36.943 0.110 0.300 0.300 1004 65.000 34.424 0.100 0.424 0.050 1005 60.000 39.445 0.108 0.100 0.345

Measurements about cutting performance, dezincification corrosion resistant performance, tensile strength, and elongation rate are performed on alloys with the above constituents in the cast state at room temperature, and the reference sample is a lead-containing brass with the same state and specification, i.e., C36000 alloy.

Results of the measurements about tensile strength, elongation rate, cutting performance, and dezincification corrosion resistant performance are listed as follow:

RELA- TENSILE ELONGA- TIVE STRENGTH TION DEZINCIFICATION CUTTING No. (N/mm²) RATE (%) LAYER RATE 1001 366 23 ⊚ ⊚ 1002 387 21 ⊚ ⊚ 1003 325 27 ⊚ ⊚ 1004 387 25 ⊚ ⊚ 1005 295 35 ◯ ⊚ C36000 394 9 X ⊚ alloy

Embodiment 2

Table 2-1 lists inventive products 2 with 5 different constituents which are fabricated with the above process, which are respectively numbered as 2001-2005, each constituent being in the unit of weight percentage (wt %).

TABLE 2-1 aluminum manganese phosphorus No. copper (Cu) zinc (Zn) lead (Pb) (Al) tin (Sn) (Mn) (P) 2001 60.000 39.137 0.144 0.312 0.055 0.050 0.300 2002 64.307 34.305 0.214 0.700 0.320 — 0.152 2003 62.221 37.467 0.250 0.521 0.089 0.500 0.050 2004 65.000 32.662 0.213 0.685 0.500 0.432 — 2005 61.331 37.922 0.100 0.100 0.050 0.443 0.252

Measurements about cutting performance, dezincification corrosion resistant performance, tensile strength, and elongation rate are performed on alloys with the above constituents in the cast state at room temperature, and the reference sample is a lead-containing brass with the same state and specification, i.e., C36000 alloy.

Results of the measurements about tensile strength, elongation rate, cutting performance, and dezincification corrosion resistant performance are listed as follow:

RELA- TENSILE ELONGA- TIVE STRENGTH TION DEZINCIFICATION CUTTING No. (N/mm²) RATE (%) LAYER RATE 2001 338 23 ⊚ ⊚ 2002 307 19 ⊚ ⊚ 2003 375 31 ◯ ⊚ 2004 381 29 ⊚ ⊚ 2005 308 17 ◯ ⊚ C36000 394 9 X ⊚ alloy

Embodiment 3

Table 3-1 lists inventive products 3 with 8 different constituents which are fabricated with the above process, which are respectively numbered as 3001-3008, each constituent being in the unit of weight percentage (wt %).

TABLE 3-1 aluminum manganese phosphorus No. copper (Cu) zinc (Zn) lead (Pb) (Al) tin (Sn) (Mn) (P) boron (B) 3001 62.400 36.395 0.220 0.542 0.152 — 0.288 0.001 3002 60.000 39.245 0.100 0.163 0.406 0.075 — 0.009 3003 64.221 34.422 0.122 0.344 0.500 0.332 0.050 0.007 3004 63.443 35.250 0.203 0.700 0.351 0.050 — 0.001 3005 63.766 34.967 0.200 0.698 0.081 — 0.286 — 3006 64.250 35.061 0.152 0.100 0.130 — 0.300 0.005 3007 60.355 38.534 0.250 0.311 0.050 0.488 — 0.010 3008 65.000 34.110 0.100 0.211 0.077 0.500 — —

Measurements about cutting performance, dezincification corrosion resistant performance, tensile strength, and elongation rate are performed on alloys with the above constituents in the cast state at room temperature, and the reference sample is a lead-containing brass with the same state and specification, i.e., C36000 alloy.

Results of the measurements about tensile strength, elongation rate, cutting performance, and dezincification corrosion resistant performance are listed as follow:

RELA- TENSILE ELONGA- TIVE STRENGTH TION DEZINCIFICATION CUTTING No. (N/mm²) RATE (%) LAYER RATE 3001 348 19 ⊚ ⊚ 3002 359 17 ⊚ ⊚ 3003 385 15 ⊚ ⊚ 3004 379 26 ⊚ ⊚ 3005 389 18 ⊚ ⊚ 3006 392 27 ⊚ ⊚ 3007 311 39 ⊚ ⊚ 3008 303 30 ⊚ ⊚ C36000 394 9 X ⊚ alloy

Embodiment 4

Table 4-1 lists inventive products 4 with 8 different constituents which are fabricated with the above process, which are respectively numbered as 4001-4008, each constituent being in the unit of weight percentage (wt %).

TABLE 4-1 aluminum manganese phosphorus No. copper (Cu) zinc (Zn) lead (Pb) (Al) tin (Sn) (Mn) (P) boron (B) 4001 61.306 37.387 0.205 0.650 0.050 0.093 0.300 0.007 4002 61.560 37.539 0.100 0.165 0.413 0.170 0.050 0.001 4003 63.750 35.015 0.193 0.371 0.500 0.057 0.107 0.005 4004 62.105 36.704 0.211 0.502 0.333 0.050 0.083 0.010 4005 65.000 33.232 0.202 0.700 0.085 0.487 0.286 0.006 4006 62.950 35.663 0.188 0.304 0.132 0.498 0.260 0.003 4007 60.000 38.802 0.250 0.387 0.111 0.138 0.300 0.010 4008 61.432 37.539 0.135 0.100 0.050 0.500 0.234 0.008

Measurements about cutting performance, dezincification corrosion resistant performance, tensile strength, and elongation rate are performed on alloys with the above constituents in the cast state at room temperature, and the reference sample is a lead-containing brass with the same state and specification, i.e., C36000 alloy.

Results of the measurements about tensile strength, elongation rate, cutting performance, and dezincification corrosion resistant performance are listed as follow:

RELA- TENSILE ELONGA- TIVE STRENGTH TION DEZINCIFICATION CUTTING No. (N/mm²) RATE (%) LAYER RATE 4001 302 29 ⊚ ⊚ 4002 319 19 ⊚ ⊚ 4003 383 23 ⊚ ⊚ 4004 344 26 ⊚ ⊚ 4005 389 27 ⊚ ⊚ 4006 332 37 ⊚ ⊚ 4007 311 39 ⊚ ⊚ 4008 303 20 ⊚ ⊚ C36000 394 9 X ⊚ alloy

Embodiment 5

Table 5-1 lists inventive products 5 with 8 different constituents which are fabricated with the above process, which are respectively numbered as 5001-5008, each constituent being in the unit of weight percentage (wt %).

TABLE 5-1 copper lead manganese aluminum phosphorus boron nickel chrome iron No. (Cu) zinc (Zn) (Pb) (Mn) (Al) tin (Sn) (P) (B) (Ni) (Cr) (Fe) 5001 61.783 37.673 0.100 0.067 0.155 0.050 0.105 0.002 — 0.065 — 5002 62.344 36.864 0.187 0.056 0.267 0.063 0.050 0.001 0.010 0.150 0.008 5003 65.000 33.638 0.250 0.500 0.100 0.172 0.211 0.010 0.007 0.097 0.015 5004 62.271 36.191 0.147 0.324 0.156 0.500 0.300 0.007 0.104 — — 5005 64.033 34.003 0.195 0.211 0.545 0.433 0.240 0.005 — 0.085 0.250 5006 63.078 34.939 0.179 0.085 0.700 0.408 0.177 0.001 0.250 0.073 0.110 5007 63.730 34.926 0.188 0.050 0.398 0.383 0.285 0.006 — 0.034 — 5008 60.000 38.865 0.158 0.075 0.400 0.217 0.102 0.008 0.062 0.008 0.105

Measurements about cutting performance, dezincification corrosion resistant performance, tensile strength, and elongation rate are performed on alloys with the above constituents in the cast state at room temperature, and the reference sample is a lead-containing brass with the same state and specification, i.e., C36000 alloy.

Results of the measurements about tensile strength, elongation rate, cutting performance, and dezincification corrosion resistant performance are listed as follow:

RELA- TENSILE ELONGA- TIVE STRENGTH TION DEZINCIFICATION CUTTING No. (N/mm²) RATE (%) LAYER RATE 5001 312 19 ⊚ ⊚ 5002 319 21 ⊚ ⊚ 5003 390 30 ⊚ ⊚ 5004 334 17 ⊚ ⊚ 5005 389 18 ⊚ ⊚ 5006 337 25 ⊚ ⊚ 5007 321 19 ⊚ ⊚ 5008 301 21 ⊚ ⊚ C36000 394 9 X ⊚ alloy

Embodiment 6

Table 6-1 lists inventive products 6 with 8 different constituents which are fabricated with the above process, which are respectively numbered as 6001-6008, each constituent being in the unit of weight percentage (wt %).

TABLE 6-1 copper manganese aluminum phosphorus No. (Cu) zinc (Zn) lead (Pb) (Mn) (Al) tin (Sn) (P) boron (B) 6001 62.311 37.687 0.103 0.105 0.100 0.050 0.211 0.009 6002 60.000 39.824 0.117 0.057 0.322 0.121 0.300 0.010 6003 62.052 37.195 0.201 0.050 0.203 0.234 0.055 0.008 6004 62.261 36.613 0.250 0.213 0.104 0.500 0.050 0.007 6005 64.075 34.316 0.207 0.304 0.556 0.432 0.103 0.005 6006 63.011 35.151 0.184 0.500 0.607 0.331 0.213 0.001 6007 65.000 33.371 0.197 0.443 0.700 0.087 0.198 0.002 6008 60.079 39.028 0.100 0.116 0.433 0.102 0.137 0.003

Measurements about cutting performance, dezincification corrosion resistant performance, tensile strength, and elongation rate are performed on alloys with the above constituents in the cast state at room temperature, and the reference sample is a lead-containing brass with the same state and specification, i.e., C36000 alloy.

Results of the measurements about tensile strength, elongation rate, cutting performance, and dezincification corrosion resistant performance are listed as follow:

RELA- TENSILE ELONGA- TIVE STRENGTH TION DEZINCIFICATION CUTTING No. (N/mm²) RATE (%) LAYER RATE 6001 344 30 ⊚ ⊚ 6002 313 31 ⊚ ⊚ 6003 340 27 ⊚ ⊚ 6004 399 17 ⊚ ⊚ 6005 351 21 ⊚ ⊚ 6006 339 23 ⊚ ⊚ 6007 355 19 ⊚ ⊚ 6008 307 21 ⊚ ⊚ C36000 394 9 X ⊚ alloy

Embodiment 7

Table 7-1 lists inventive products 7 with 8 different constituents which are fabricated with the above process, which are respectively numbered as 7001-7008, each constituent being in the unit of weight percentage (wt %).

TABLE 7-1 copper manganese aluminum phosphorus No. (Cu) zinc (Zn) lead (Pb) (Mn) (Al) tin (Sn) (P) boron (B) 7001 60.231 38.981 0.100 0.341 0.112 0.103 0.122 0.008 7002 61.054 38.264 0.196 0.117 0.231 0.076 0.050 0.010 7003 62.013 36.904 0.133 0.500 0.100 0.050 0.292 0.006 7004 62.613 35.805 0.100 0.493 0.540 0.143 0.300 0.004 7005 65.000 33.525 0.211 0.050 0.631 0.500 0.076 0.005 7006 63.011 35.287 0.250 0.210 0.700 0.410 0.123 0.007 7007 60.000 38.747 0.201 0.077 0.487 0.377 0.100 0.009 7008 61.123 37.779 0.197 0.192 0.391 0.218 0.097 0.001

Measurements about cutting performance, dezincification corrosion resistant performance, tensile strength, and elongation rate are performed on alloys with the above constituents in the cast state at room temperature, and the reference sample is a lead-containing brass with the same state and specification, i.e., C36000 alloy.

Results of the measurements about tensile strength, elongation rate, cutting performance, and dezincification corrosion resistant performance are listed as follow:

RELA- TENSILE ELONGA- TIVE STRENGTH TION DEZINCIFICATION CUTTING No. (N/mm²) RATE (%) LAYER RATE 7001 327 23 ⊚ ⊚ 7002 332 17 ⊚ ⊚ 7003 341 18 ⊚ ⊚ 7004 354 31 ⊚ ⊚ 7005 397 37 ⊚ ⊚ 7006 393 39 ⊚ ⊚ 7007 300 28 ⊚ ⊚ 7008 301 27 ⊚ ⊚ C36000 394 9 X ⊚ alloy

Embodiment 8

Table 8-1 lists inventive products 8 with 8 different constituents which are fabricated with the above process, which are respectively numbered as 8001-8008, each constituent being in the unit of weight percentage (wt %).

TABLE 8-1 copper manganese aluminum phosphorus No. (Cu) zinc (Zn) lead (Pb) (Mn) (Al) tin (Sn) (P) boron (B) 8001 60.000 39.615 0.105 0.052 0.123 — 0.102 0.001 8002 62.031 37.395 0.197 0.121 0.100 0.102 0.050 — 8003 62.178 36.995 0.250 0.455 — 0.112 — 0.008 8004 65.000 33.839 0.100 0.500 0.341 0.050 0.158 0.010 8005 64.175 35.328 0.211 — — — 0.277 0.007 8006 64.097 34.142 0.233 0.314 0.407 0.500 0.300 0.005 8007 63.050 35.487 0.102 0.218 0.518 0.411 0.212 — 8008 61.071 38.101 0.112 0050 0.700 — — 0.009

Measurements about cutting performance, dezincification corrosion resistant performance, tensile strength, and elongation rate are performed on alloys with the above constituents in the cast state at room temperature, and the reference sample is a lead-containing brass with the same state and specification, i.e., C36000 alloy.

Results of the measurements about tensile strength, elongation rate, cutting performance, and dezincification corrosion resistant performance are listed as follow:

RELA- TENSILE ELONGA- TIVE STRENGTH TION DEZINCIFICATION CUTTING No. (N/mm²) RATE (%) LAYER RATE 8001 302 23 ⊚ ⊚ 8002 311 27 ⊚ ⊚ 8003 345 32 ⊚ ⊚ 8004 342 24 ⊚ ⊚ 8005 367 37 ⊚ ⊚ 8006 366 29 ⊚ ⊚ 8007 339 31 ⊚ ⊚ 8008 307 27 ⊚ ⊚ C36000 394 9 X ⊚ alloy

Embodiment 9

Table 9-1 lists inventive products 9 with 8 different constituents which are fabricated with the above process, which are respectively numbered as 9001-9008, each constituent being in the unit of weight percentage (wt %).

TABLE 9-1 copper lead manganese aluminum phosphorus boron nickel chrome iron No. (Cu) zinc (Zn) (Pb) (Mn) (Al) tin (Sn) (P) (B) (Ni) (Cr) (Fe) 9001 61.058 38.409 0.112 — — 0.098 0.073 — — — 0.250 9002 62.025 36.933 0.109 0.102 0.500 0.050 0.050 0.010 0.009 0.113 0.099 9003 60.000 39.554 0.100 0.050 — — — 0.007 0.215 — 0.074 9004 61.256 36.743 0.207 0.321 0.700 0.134 0.231 0.008 0.250 0.150 — 9005 65.000 34.019 0.198 0.076 0.100 — 0.300 — 0.125 0.078 0.104 9006 63.056 34.935 0.222 0.500 0.214 0.500 0.289 0.001 0.123 0.043 0.117 9007 63.340 35.447 0.250 — 0.566 — 0.250 0.004 0.143 — — 9008 60.870 37.906 0.234 — 0.452 0.430 — — — 0.108 —

Measurements about cutting performance, dezincification corrosion resistant performance, tensile strength, and elongation rate are performed on alloys with the above constituents in the cast state at room temperature, and the reference sample is a lead-containing brass with the same state and specification, i.e., C36000 alloy.

Results of the measurements about tensile strength, elongation rate, cutting performance, and dezincification corrosion resistant performance are listed as follow:

RELA- TENSILE ELONGA- TIVE STRENGTH TION DEZINCIFICATION CUTTING No. (N/mm²) RATE (%) LAYER RATE 9001 317 27 ⊚ ⊚ 9002 324 19 ⊚ ⊚ 9003 303 17 ⊚ ⊚ 9004 378 36 ⊚ ⊚ 9005 389 17 ⊚ ⊚ 9006 332 37 ⊚ ⊚ 9007 391 39 ⊚ ⊚ 9008 303 21 ⊚ ⊚ C36000 394 9 X ⊚ alloy

Embodiment 10

Table 10-1 lists inventive products 1 with 5 different constituents which are fabricated with the above process0, which are respectively numbered as 10001-10005, each constituent being in the unit of weight percentage (wt %).

TABLE 10-1 phosphorus No. copper (Cu) zinc (Zn) lead (Pb) tin (Sn) (P) 10001 60.000 39.740 0.113 0.089 0.056 10002 62.345 37.272 0.100 0.050 0.231 10003 65.000 33.964 0.234 0.500 0.300 10004 61.983 37.366 0.247 0.324 0.078 10005 64.037 35.552 0.250 0.109 0.050

Measurements about cutting performance, dezincification corrosion resistant performance, tensile strength, and elongation rate are performed on alloys with the above constituents in the cast state at room temperature, and the reference sample is a lead-containing brass with the same state and specification, i.e., C36000 alloy.

Results of the measurements about tensile strength, elongation rate, cutting performance, and dezincification corrosion resistant performance are listed as follow:

RELA- TENSILE ELONGA- TIVE STRENGTH TION DEZINCIFICATION CUTTING No. (N/mm²) RATE (%) LAYER RATE 10001 300 29 ⊚ ⊚ 10002 337 19 ⊚ ⊚ 10003 389 33 ⊚ ⊚ 10004 364 26 ⊚ ⊚ 10005 379 27 ⊚ ⊚ C36000 394 9 X ⊚ alloy

Embodiment 11

Table 11-1 lists inventive products 11 with 8 different constituents which are fabricated with the above process, which are respectively numbered as 11001-11008, each constituent being in the unit of weight percentage (wt %).

TABLE 11-1 copper manganese aluminum phosphorus No. (Cu) zinc (Zn) lead (Pb) (Mn) (Al) tin (Sn) (P) boron (B) 11001 63.521 36.133 0.119 0.098 — 0.067 0.050 0.010 11002 62.143 37.196 0.234 0.050 0.198 0.054 0.123 — 11003 60.000 39.228 0.235 0.178 0.100 0.103 0.150 0.006 11004 63.015 35.844 0.200 — 0.655 0.050 0.231 0.003 11005 65.000 33.061 0.250 0.500 0.543 0.343 0.300 0.001 11006 61.197 37.214 0.179 0.377 0.433 0.500 0.098 — 11007 61.132 37.588 0.150 0.236 0.231 0.476 0.178 0.007 11008 62.273 36.599 0.100 — 0.700 0.214 0.104 0.008

Measurements about cutting performance, dezincification corrosion resistant performance, tensile strength, and elongation rate are performed on alloys with the above constituents in the cast state at room temperature, and the reference sample is a lead-containing brass with the same state and specification, i.e., C36000 alloy.

Results of the measurements about tensile strength, elongation rate, cutting performance, and dezincification corrosion resistant performance are listed as follow:

RELA- TENSILE ELONGA- TIVE STRENGTH TION DEZINCIFICATION CUTTING No. (N/mm²) RATE (%) LAYER RATE 11001 361 23 ⊚ ⊚ 11002 354 33 ⊚ ⊚ 11003 317 39 ⊚ ⊚ 11004 336 36 ⊚ ⊚ 11005 401 41 ⊚ ⊚ 11006 321 26 ⊚ ⊚ 11007 300 23 ⊚ ⊚ 11008 341 21 ⊚ ⊚ C36000 394 9 X ⊚ alloy

Embodiment 12

Table 12-1 lists inventive products 12 with 8 different constituents which are fabricated with the above process, which are respectively numbered as 12001-12008, each constituent being in the unit of weight percentage (wt %).

TABLE 2-1 copper lead manganese aluminum phosphorus boron nickel chrome iron No. (Cu) zinc (Zn) (Pb) (Mn) (Al) tin (Sn) (P) (B) (Ni) (Cr) (Fe) 12001 61.148 38.358 0.250 0.098 — 0.088 0.050 0.005 — — 0.003 12002 62.434 36.989 0.123 0.050 0.102 0.103 0.076 0.001 0.122 — — 12003 60.000 39.131 0.108 — 0.234 0.231 0.136 0.010 — 0.150 — 12004 60.166 38.272 0.197 0.232 — 0.455 0.220 0.007 0.250 0.098 0.103 12005 60.000 37.850 0.100 0.341 0.452 0.500 0.300 — 0.207 — 0.250 12006 62.126 36.129 0.102 0.500 0.100 0.341 0.276 0.006 0.198 0.109 0.113 12007 65.000 33.876 0.113 — 0.673 0.122 0.087 0.009 0.113 0.007 — 12008 61.430 37.130 0.150 0.476 0.700 0.050 0.059 — — 0.004 0.001

Measurements about cutting performance, dezincification corrosion resistant performance, tensile strength, and elongation rate are performed on alloys with the above constituents in the cast state at room temperature, and the reference sample is a lead-containing brass with the same state and specification, i.e., C36000 alloy.

Results of the measurements about tensile strength, elongation rate, cutting performance, and dezincification corrosion resistant performance are listed as follow:

RELA- TENSILE ELONGA- TIVE STRENGTH TION DEZINCIFICATION CUTTING No. (N/mm²) RATE (%) LAYER RATE 12001 312 29 ⊚ ⊚ 12002 317 19 ⊚ ⊚ 12003 303 13 ⊚ ⊚ 12004 314 16 ⊚ ⊚ 12005 309 17 ⊚ ⊚ 12006 332 28 ⊚ ⊚ 12007 391 29 ⊚ ⊚ 12008 311 21 ⊚ ⊚ C36000 394 9 X ⊚ alloy

As can be seen, the lead-free bismuth-free silicon-free brass alloy of the invention can be formed by adding various constituents in respective ratio, and then subjecting them to a process in a high-frequency melting furnace. The resulting brass alloy has a mechanical processability which is comparable with that of the existing lead-containing brass, has an excellent tensile strength, elongation rate, and dezincification resistance, and has a low content of lead. As a result, the brass alloy is suitable for replacing the existing lead-containing brass alloy and for producing parts like faucet and sanitary ware.

Although the invention has been described with respect to embodiments thereof, these embodiments do not intend to limit the invention. The ordinary skilled in the art can made modifications and changes to the invention without departing from the spirit and scope of the invention. Thus, the protection of the invention is defined by the appended claims. 

1. A low-lead bismuth-free silicon-free brass alloy with excellent cutting performance, characterized by comprising: by the total weight of the brass alloy, 60-65 wt % copper, 0.1-0.25 wt % lead, 0.1-0.7 wt % aluminum and 0.05-0.5 wt % tin, and a balance of zinc.
 2. The brass alloy of claim 1, characterized by further comprising 0.05-0.5 wt % manganese and/or 0.05-0.3 wt % phosphorus by the total weight of the brass alloy.
 3. The brass alloy of claim 1, characterized by further comprising one or more element selected from the group consisting of 0.05-0.3 wt % phosphorus, 0.05-0.5 wt % manganese and 0.001-0.01 wt % boron by the total weight of the brass alloy.
 4. The brass alloy of claim 1, characterized by further comprising 0.05-0.3 wt % phosphorus, 0.05-0.5 wt % manganese and 0.001-0.01 wt % boron by the total weight of the brass alloy.
 5. The brass alloy of claim 4, characterized by further comprising: unavoidable impurities which comprise, by the total weight of the brass alloy, 0.25 wt % or less nickel, 0.15 wt % or less chrome and/or 0.25 wt % or less iron.
 6. The brass alloy of claim 4, characterized in that a total content of manganese, aluminum, tin, phosphorus and boron is not larger than 2 wt % of the total weight of the brass alloy.
 7. The brass alloy of claim 6, characterized in that the total content of manganese, aluminum, tin, phosphorus and boron is not less than 0.1 wt % of the total weight of the brass alloy.
 8. A low-lead bismuth-free silicon-free brass alloy with excellent cutting performance, characterized by comprising: by the total weight of the brass alloy, 60-65 wt % copper, 0.1-0.25 wt % lead, two or more elements selected from the group consisting of 0.1-0.7 wt % aluminum, 0.05-0.5 wt % tin, 0.05-0.3 wt % phosphorus, 0.05-0.5 wt % manganese and 0.001-0.01 wt % boron, and a balance of zinc.
 9. The brass alloy of claim 8, characterized by further comprising: unavoidable impurities which comprise, by the total weight of the brass alloy, 0.25 wt % or less nickel, 0.15 wt % or less chrome and/or 0.25 wt % or less iron.
 10. A low-lead bismuth-free silicon-free brass alloy with excellent cutting performance, characterized by comprising: 60-65 wt % copper, 0.1-0.25 wt % lead, 0.05-0.5 wt % tin and 0.05-0.3 wt % phosphorus by the total weight of the brass alloy, and a balance of zinc.
 11. The brass alloy of claim 10, characterized by further comprising two or more elements selected from the group consisting of 0.1-0.7 wt % aluminum, 0.05-0.5 wt % manganese and 0.001-0.01 wt % boron by the total weight of the brass alloy.
 12. The brass alloy of claim 11, characterized by further comprising: unavoidable impurities which comprise, by the total weight of the brass alloy, 0.25 wt % or less nickel, 0.15 wt % or less chrome and/or 0.25 wt % or less iron. 